Eversource, CL&P, NSTAR Electric and PSNH are subject to environmental laws and regulations intended to mitigate or remove the effect of past operations and improve or maintain the quality of the environment. These laws and regulations require the removal or the remedy of the effect on the environment of the disposal or release of certain specified hazardous substances at current and former operating sites. Eversource, CL&P, NSTAR Electric and PSNH have an active environmental auditing and training program and each believes it is substantially in compliance with all enacted laws and regulations.

Included in the number of sites and reserve amounts above are former MGP sites that were operated several decades ago and manufactured natural gas from coal and other processes, which resulted in certain by-products remaining in the environment that may pose a potential risk to human health and the environment, for which Eversource may have potential liability. Eversource’s reserve balances related to these former MGP sites were $139.9 million and $140.9 million as of March 31, 2026 and December 31, 2025, respectively, and related primarily to the natural gas business segment.

These reserve estimates are subjective in nature as they take into consideration several different remediation options at each specific site. The reliability and precision of these estimates can be affected by several factors, including new information concerning either the level of contamination at the site, the extent of Eversource's, CL&P's, NSTAR Electric's and PSNH's responsibility for remediation or the extent of remediation required, recently enacted laws and regulations or changes in cost estimates due to certain economic factors. It is possible that new information or future developments could require a reassessment of the potential exposure to required environmental remediation. As this information becomes available, management will continue to assess the potential exposure and adjust the reserves accordingly.

Guarantees issued on behalf of unconsolidated entities, including equity method ownership interests, for which Eversource parent is the guarantor, are recorded at fair value as a liability on the balance sheet at the inception of the guarantee. The fair value of guarantees issued on behalf of unconsolidated entities are recorded within Other Long-Term Liabilities on the balance sheet, and were $1.2 million and $1.3 million as of March 31, 2026 and December 31, 2025, respectively. Eversource regularly reviews performance risk under these guarantee arrangements, and believes the likelihood of payments being required under the guarantees is remote. In the event it becomes probable that Eversource parent will be required to perform under the guarantee, the amount of probable payment will be recorded.

On September 30, 2024, Eversource completed the sale of its 50 percent ownership share in the South Fork Wind and Revolution Wind projects to affiliates of Global Infrastructure Partners (GIP). Under the agreement with GIP, Eversource’s existing and certain additional credit support obligations for Revolution Wind are expected to roll off as the project completes construction. On July 9, 2024, Eversource completed the sale of its 50 percent ownership share of Sunrise Wind to Ørsted. Under the agreement with Ørsted, Eversource’s existing credit support obligations for Sunrise Wind were either terminated or indemnified by Ørsted as a result of the sale.

The following table summarizes Eversource parent's exposure to guarantees and indemnifications of its subsidiaries and affiliates to external parties, and primarily relates to its previously-owned offshore wind investments:

As of March 31, 2026

Company (Obligor)

Description

Maximum Exposure
(in millions)

Revolution Wind, LLC and TurbineCo, LLC

Offshore wind construction-related purchase agreements with third-party contractors (1)

122.3

Eversource Investment LLC, Eversource Investment Service Company LLC and South Fork Class B Member, LLC

Offshore wind funding and indemnification obligations (2)

143.0

Eversource Investment LLC

Revolution Wind Tax Positions (3)

300.0

Eversource TEI LLC

South Fork Wind Tax Equity (4)

50.0

South Fork Wind, LLC

Power Purchase Agreement Security (5)

7.1

Various Eversource subsidiaries

Surety bonds (6)

34.1

(1) Eversource parent issued guarantees on behalf of its previously 50 percent-owned affiliate, Revolution Wind, LLC, and on behalf of TurbineCo, LLC (successor in interest to North East Offshore, LLC (NEO)), under which Eversource parent agreed to guarantee each entity’s performance of obligations under certain construction-related purchase agreements with third-party contractors, in an aggregate amount not to exceed $682.7 million. Eversource parent’s obligations under the guarantees expire upon the earlier of (i) dates ranging between October 2027 and November 2027 and (ii) full performance of the guaranteed obligations.

(2) Eversource parent issued guarantees on behalf of its wholly-owned subsidiary Eversource Investment LLC (EI), which held Eversource's previous investments in offshore wind-related equity method investments until sale, and on behalf of its previously 50 percent-owned affiliate, South Fork Class B Member, LLC, whereby Eversource parent will guarantee each entity’s performance of certain funding obligations of the South Fork and Revolution Wind projects. Eversource parent also guaranteed certain indemnification obligations of EI associated with third-party credit support for EI’s investment in NEO. On September 30, 2024, Eversource parent issued a guaranty on behalf of its wholly-owned subsidiary, Eversource Investment Service Company LLC, whereby Eversource parent will guarantee Eversource Investment Service Company LLC’s performance of certain indemnification obligations during the onshore construction phase of the Revolution Wind project, in an amount not to exceed $100.0 million. These guarantees will not exceed $1.62 billion and expire upon the full performance of the guaranteed obligations.

(4) Eversource parent issued a guarantee on behalf of its wholly-owned subsidiary, Eversource TEI LLC, whereby Eversource parent will guarantee Eversource TEI LLC’s performance of certain obligations, in an amount not to exceed $50.0 million, in connection with any remaining obligations under the LLC agreement. Eversource parent’s obligations expire upon the full performance of the guaranteed obligations.

(5) Eversource parent issued a guarantee on behalf of its previously 50 percent-owned affiliate, South Fork Wind, LLC, whereby Eversource parent will guarantee South Fork Wind, LLC's performance of certain obligations, in an amount not to exceed $7.1 million, under a Power Purchase Agreement between the Long Island Power Authority and South Fork Wind, LLC (the Agreement). The guarantee expires upon the later of (i) the end of the Agreement term, January 2044, with the option to extend to January 2049 and (ii) full performance of the guaranteed obligations.

Eversource parent entered into a guarantee on behalf of EI, under which Eversource parent would guarantee EI’s obligations under a letter of credit facility with a financial institution that EI may request in an aggregate amount of up to approximately $25 million. As of March 31, 2026, there are no letters of credit issued under this guarantee. The guarantee will remain in effect until full performance of the guaranteed obligations.

Four separate complaints were filed at the FERC by combinations of New England state attorneys general, state regulatory commissions, consumer advocates, consumer groups, municipal parties and other parties (collectively, the Complainants). In each of the first three complaints, filed on October 1, 2011, December 27, 2012, and July 31, 2014, respectively, the Complainants challenged the New England Transmission Owners’ (NETOs’) base return on equity (ROE) of 11.14 percent that had been utilized since 2006 and sought an order to reduce it prospectively from the date of the final FERC order and for the separate 15-month complaint periods. In the fourth complaint, filed April 29, 2016, the Complainants challenged the NETOs' base ROE billed of 10.57 percent and the maximum ROE including transmission incentives (incentive cap) of 11.74 percent, asserting that these ROEs were unjust and unreasonable.

The ROE originally billed during the period October 1, 2011 (beginning of the first complaint period) through October 15, 2014 consisted of a base ROE of 11.14 percent and incentives up to 13.1 percent. On October 16, 2014, FERC issued Opinion No. 531-A and set the base ROE at 10.57 percent and the incentive cap at 11.74 percent for the first complaint period. This was also effective for all prospective billings to customers beginning October 16, 2014. The NETOs filed an appeal of this decision, which was vacated on April 14, 2017 by the U.S. Court of Appeals for the D.C. Circuit (the D.C. Circuit Court). All amounts associated with Opinion No. 531-A on the first complaint period lowering the base ROE of 11.14 percent to 10.57 percent were refunded by 2015.

On October 16, 2018, FERC issued an order on all four complaints describing how it intended to address the issues that were remanded by the D.C. Circuit Court. FERC proposed a new framework to determine (1) whether an existing ROE is unjust and unreasonable and, if so, (2) how to calculate a replacement ROE. The FERC order included illustrative calculations for the first complaint using FERC's proposed frameworks with financial data from that complaint. Those illustrative calculations indicated that for the first complaint period, the preliminary just and reasonable base ROE for the NETOs, which FERC concludes are of average financial risk, is 10.41 percent and the preliminary incentive cap on total ROE is 13.08 percent.

On March 19, 2026, FERC issued Opinion No. 594 in the NETO ROE proceedings, attempting to resolve all four pending complaints dating back to 2011 and respond to the D.C. Circuit Court’s April 14, 2017 decision vacating FERC’s prior decision in the first complaint, which found that the FERC had failed to (1) make an explicit, reasoned finding that the then-existing 11.14 percent base ROE was unjust and unreasonable before imposing a replacement ROE, and (2) adequately justify placing the ROE at the midpoint of the upper half of the zone of reasonableness. In Opinion No. 594, FERC applied a revised ROE methodology that it believes is consistent with its 2024 ROE Order on remand to the Midcontinent ISO (MISO) transmission owners, to satisfy the first step in the FERC process to revise the ROE in a Section 206 proceeding by finding the NETOs’ base ROE of 11.14 percent is unjust and unreasonable. FERC then found the just and reasonable replacement base ROE to be 9.57 percent with an incentive cap of 12.09 percent for the first complaint period (October 1, 2011 – December 31, 2012) and applied this same ROE prospectively, effective October 16, 2014, the date of the first complaint order vacated by the D.C. Circuit Court. FERC directed the NETOs to issue refunds with interest for the applicable refund periods. This decision decreases the allowed base ROE of 10.57 percent with an incentive cap of 11.74 percent to a base ROE of 9.57 percent with an incentive cap of 12.09 percent. The second, third and fourth NETO ROE complaints were dismissed as part of the decision and FERC did not direct any refunds for the periods associated with those proceedings.

On April 20, 2026, the NETOs submitted to FERC a request for rehearing of Opinion No. 594 to reconsider its decision by highlighting several deficiencies including but not limited to the unlawful retroactive refund period with interest extended beyond the 15-month statutory relief authority granted in Section 206(b) of the Federal Power Act, the FERC not proving that the previously approved 11.14 percent base ROE was unjust and unreasonable as remanded by the D.C. Circuit Court, the flawed methodologies applied in setting the replacement 9.57 percent base ROE, failing to comply with the requirement for FERC to use data that is relevant to the current period at the time of the decision for the NETOs’ going forward ROE, and procedural issues related to overlapping complaints.

On April 30, 2026, the NETOs submitted a Federal Power Act Section 205 filing to FERC, which is a formal request by a public utility to change the ROE rate prospectively and requires the utility to prove the proposed change is just and reasonable. The NETOs proposed a replacement ROE of 11.39 percent, resulting in a cap of 12.89 percent including incentives, which is based on current market data utilizing FERC’s ROE methodology from Opinion No. 594. The NETOs requested an effective date of June 30, 2026. FERC has 60 days to act on the rate proposal and can suspend the proposed rate change for up to five months after the initial 60-day notice. If a settlement is not reached among the parties to the FERC proceeding, Eversource would begin billing the proposed ROE by December 2026 on a subject-to-refund basis after the completion of a hearing on the matter.

As a result of the March 19, 2026 FERC decision, Eversource has determined that a loss is probable and that a range of loss is reasonably estimable. Based on Eversource’s current evaluation of the relevant facts and circumstances, the Company has estimated a range of reasonably possible pre-tax losses of $60.4 million to $932 million, which includes a range of interest of $28.8 million to $256 million, as of March 31, 2026. The low end of the estimated range of loss reflects estimated refunds associated with the fifteen-month first complaint period, including interest. The high end of the estimated range of loss includes the refunds associated with the first complaint period, as well as estimated refunds for the retroactive refund period from October 16, 2014 through March 19, 2026, including interest, in the pre-tax amount of approximately $871 million. The range of loss estimates use the 9.57 percent replacement ROE and incentive cap of 12.09 percent prescribed in the March 19, 2026 FERC decision. Based on Eversource’s legal assessment of the Federal Power Act and the legal and regulatory deficiencies underlying this decision as identified in the rehearing request, including that the retroactive application is inconsistent with the statutory limitations under the Federal Power Act, Eversource does not believe that refunds at the high end of the range for the retroactive period are probable. Eversource continues to challenge the March 19, 2026 FERC decision, but cannot predict the ultimate outcome of these proceedings.

The Company has recorded a current regulatory liability for revenues subject to refund of $60.4 million (pre-tax) as of March 31, 2026, which represents the low end of the range, as no amount within this range is considered a better estimate. The liability recorded reflects the difference between the billed 10.57 percent base ROE and the new 9.57 percent base ROE for the first complaint period, including interest. The liability consists of $28.7 million, $24.2 million and $7.5 million for CL&P, NSTAR Electric and PSNH, respectively, of which $13.7 million, $11.5 million and $3.6 million is accrued interest, respectively, as of March 31, 2026. The revenues subject to refund were recorded as a reduction to Operating Revenues and the accrued interest was recorded as an increase to Interest Expense in the statements of income. Eversource does not have any other reserves recorded for the other complaint periods, as these remaining complaints were dismissed.

The Company’s estimates are based on currently available information; however, it is reasonably possible that the ultimate resolution of this matter may result in a loss in excess of the amount accrued, and such additional losses could have a material impact on the financial condition, results of operations, and cash flows in a future period.

CL&P, NSTAR Electric and PSNH have plant closure and fuel storage cost obligations to the Yankee Companies, which have each completed the physical decommissioning of their respective nuclear power facilities and are now engaged in the long-term storage of their spent fuel. The Yankee Companies fund these costs through litigation proceeds received from the DOE and, to the extent necessary, through wholesale, FERC-approved rates charged under power purchase agreements with several New England utilities, including CL&P, NSTAR Electric and PSNH. CL&P, NSTAR Electric and PSNH, in turn recover these costs from their customers through state regulatory commission-approved retail rates. The Yankee Companies collect amounts that management believes are adequate to recover the remaining plant closure and fuel storage cost estimates for the respective plants. Management believes CL&P and NSTAR Electric will recover their shares of these obligations from their customers. PSNH has recovered its total share of these costs from its customers.

The Yankee Companies have filed complaints against the DOE in the Court of Federal Claims seeking monetary damages resulting from the DOE's failure to accept delivery of, and provide for a permanent facility to store, spent nuclear fuel pursuant to the terms of the 1983 spent fuel and high-level waste disposal contracts between the Yankee Companies and the DOE. The court previously awarded the Yankee Companies damages for Phases I, II, III, and IV of litigation resulting from the DOE's failure to meet its contractual obligations. These Phases covered damages incurred in the years 1998 through 2016, and the awarded damages have been received by the Yankee Companies with certain amounts of the damages refunded to their customers.

DOE Phase V Damages - In March 2021, the Yankee Companies filed Phase V lawsuits against the DOE seeking damages for its continued failure to accept spent nuclear fuel, later expanding the claims to include 2021 costs, bringing total claimed damages to $153.5 million. The parties reached a $145 million agreement in principle to settle the Phase V complaint, approved in November 2024. The Department of Justice filed a notice of appeal in January 2025 on an issue outside the scope of the settlement, with oral arguments expected in 2026.

DOE Phase VI Damages – On March 31, 2026, each of the Yankee Companies filed a sixth set of lawsuits against the DOE in the Court of Federal Claims. The Yankee Companies are seeking monetary damages for CYAPC, YAEC and MYAPC, resulting from the DOE’s failure to begin accepting spent nuclear fuel for disposal covering the years from 2022 to 2025 (DOE Phase VI).

On July 9, 2024, Eversource completed the sale of its 50 percent ownership share of Sunrise Wind to Ørsted for adjusted proceeds of $152 million. Ørsted paid Eversource $118 million at the closing of the sale transaction and remaining proceeds of $34 million will be paid after onshore construction is completed and certain other construction milestones are achieved. With completion of the sale, Eversource does not have any ongoing financial obligations associated with Sunrise Wind.

On September 30, 2024, Eversource completed the sale of its 50 percent ownership share in the South Fork Wind and Revolution Wind projects to GIP for adjusted gross proceeds of $745 million, which were received at closing. As part of the sale, Eversource and GIP agreed to make certain post-closing purchase price adjustment payments that will impact the final purchase price. The post-closing purchase price adjustment payments include cost sharing obligations that require Eversource to share equally in GIP’s funding obligations up to an effective cap of approximately $240 million of incremental capital expenditure overruns incurred during the construction phase for Revolution Wind, after which Eversource will have responsibility for GIP’s obligations for any additional capital expenditure overruns in excess of this amount. The purchase price is also subject to post-closing adjustments as a result of final project economics, which includes Eversource’s obligation to maintain GIP’s internal rate of return through the construction period for each project as specified in the agreement. For Revolution Wind, purchase price adjustment payments are expected to be completed in late 2026. South Fork Wind has achieved commercial operation, and Eversource made a purchase price adjustment payment related to this project in June 2025. All matters relating to South Fork Wind have been resolved with no material impacts.

Upon the completion of the sales in 2024, Eversource recorded a contingent liability of $365 million, reflecting its estimate of the future obligations under the terms of the sale to GIP. The total sales proceeds were compared to the carrying value of the investments, including the estimate of liability for-post-closing adjustment payments to GIP, and Eversource recognized an aggregate after-tax loss on the sales of its offshore wind investments of $524 million, which included a net $60 million increase in income tax expense including an increase in the valuation allowance for unused capital losses in 2024.

In the third quarter of 2025, Eversource received an updated report from GIP on the construction status of Revolution Wind, which included revised projections of total construction costs. The revised cost projections reflected known and quantifiable cost increases, including those associated with the impacts of damage to the wind turbine installation vessel, insurance costs, tariff impacts, and costs incurred as a result of the stop-work order for Revolution Wind received on August 22, 2025 from the Bureau of Ocean Energy Management that halted all offshore wind construction activities through September 22, 2025. Based on those developments, Eversource recognized a pre-tax charge of $284 million in the third quarter of 2025 as a result of the aggregate impact of these items to increase the liability for purchase price adjustments associated with the offshore wind projects.

Eversource continually evaluates the contingent liability and will reassess the balance as new information becomes available. Based on most recent updates from GIP on the construction status of Revolution Wind, factoring in estimated costs incurred as a result of a second stop-work order for Revolution Wind received on December 22, 2025 and removed on January 12, 2026, revised insurance estimates, and other information currently available, Eversource believes that the contingent liability balance as of March 31, 2026 is an adequate estimate to cover this contingent liability for purchase price adjustments. As of March 31, 2026 and December 31, 2025, the contingent liability totaled $298.2 million and $448.2 million, respectively, and is recorded as a current liability on Eversource’s balance sheets, based upon the timing of expected payments to GIP.

New information or future developments that arise as the construction of Revolution Wind progresses will necessitate a reassessment of the estimated liability to GIP. The Company reviews available projections of total construction costs, including the latest cost estimates and project timeline, to determine if any changes to this liability are warranted.

It is reasonably possible that as additional updated cost estimates become available, and if additional cost overruns materialize or other adverse changes in facts, regulations and circumstances occur, there could be additional losses and increases to the offshore wind contingent liability, which could be material. The Company will continue to monitor developments and evaluate potential exposures related to this contingency and will revise its estimated liability as additional information becomes available.

Contingencies are evaluated using the best information available at the time the financial statements are published, and this assessment involves judgments and assumptions about future events. Factors that could increase the obligation to GIP include construction cost overruns for Revolution Wind as well as the timing and extent of construction delays, which would impact the economics associated with the purchase price adjustment, and the eligibility for federal investment tax credits for Revolution Wind at a value lower than assumed and included in the purchase price. The purchase price of Revolution Wind included the sales value related to a 40 percent level of federal investment tax credits. A change in the expected value or qualification of investment tax credit adders could result in a significant loss in a future period.